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Commit af512ed0 authored by Ralph Wuerthner's avatar Ralph Wuerthner Committed by Martin Schwidefsky
Browse files

[S390] zcrypt: fix request timeout handling 



Under very high load zcrypt requests may timeout while waiting on the
request queue. Modify zcrypt that timeouts are based on crypto adapter
responses. A timeout occurs only if a crypto adapter does not respond
within a given time frame to sumitted requests.

Signed-off-by: default avatarRalph Wuerthner <rwuerthn@de.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent 987ad70a

drivers/s390/crypto/ap_bus.c

+89 −9
Original line number Diff line number Diff line
@@ -43,6 +43,7 @@ static void ap_poll_all(unsigned long); 
static void ap_poll_timeout(unsigned long);

static int ap_poll_thread_start(void);

static void ap_poll_thread_stop(void);

static void ap_request_timeout(unsigned long);



/**

 * Module description.
@@ -189,6 +190,7 @@ int ap_send(ap_qid_t qid, unsigned long long psmid, void *msg, size_t length) 
	case AP_RESPONSE_NORMAL:

		return 0;

	case AP_RESPONSE_Q_FULL:

	case AP_RESPONSE_RESET_IN_PROGRESS:

		return -EBUSY;

	default:	/* Device is gone. */

		return -ENODEV;
@@ -252,6 +254,8 @@ int ap_recv(ap_qid_t qid, unsigned long long *psmid, void *msg, size_t length) 
		if (status.queue_empty)

			return -ENOENT;

		return -EBUSY;

	case AP_RESPONSE_RESET_IN_PROGRESS:

		return -EBUSY;

	default:

		return -ENODEV;

	}
@@ -326,11 +330,12 @@ static int ap_init_queue(ap_qid_t qid) 
			i = AP_MAX_RESET;	/* return with -ENODEV */

			break;

		case AP_RESPONSE_RESET_IN_PROGRESS:

			rc = -EBUSY;

		case AP_RESPONSE_BUSY:

		default:

			break;

		}

		if (rc != -ENODEV)

		if (rc != -ENODEV && rc != -EBUSY)

			break;

		if (i < AP_MAX_RESET - 1) {

			udelay(5);
@@ -340,6 +345,40 @@ static int ap_init_queue(ap_qid_t qid) 
	return rc;

}



/**

 * Arm request timeout if a AP device was idle and a new request is submitted.

 */

static void ap_increase_queue_count(struct ap_device *ap_dev)

{

	int timeout = ap_dev->drv->request_timeout;



	ap_dev->queue_count++;

	if (ap_dev->queue_count == 1) {

		mod_timer(&ap_dev->timeout, jiffies + timeout);

		ap_dev->reset = AP_RESET_ARMED;

	}

}



/**

 * AP device is still alive, re-schedule request timeout if there are still

 * pending requests.

 */

static void ap_decrease_queue_count(struct ap_device *ap_dev)

{

	int timeout = ap_dev->drv->request_timeout;



	ap_dev->queue_count--;

	if (ap_dev->queue_count > 0)

		mod_timer(&ap_dev->timeout, jiffies + timeout);

	else

		/**

		 * The timeout timer should to be disabled now - since

		 * del_timer_sync() is very expensive, we just tell via the

		 * reset flag to ignore the pending timeout timer.

		 */

		ap_dev->reset = AP_RESET_IGNORE;

}



/**

 * AP device related attributes.

 */
@@ -498,6 +537,7 @@ static int ap_device_remove(struct device *dev) 
	struct ap_driver *ap_drv = ap_dev->drv;



	ap_flush_queue(ap_dev);

	del_timer_sync(&ap_dev->timeout);

	if (ap_drv->remove)

		ap_drv->remove(ap_dev);

	spin_lock_bh(&ap_device_lock);
@@ -759,17 +799,21 @@ static void ap_scan_bus(struct work_struct *unused) 
				      __ap_scan_bus);

		rc = ap_query_queue(qid, &queue_depth, &device_type);

		if (dev) {

			if (rc == -EBUSY) {

				set_current_state(TASK_UNINTERRUPTIBLE);

				schedule_timeout(AP_RESET_TIMEOUT);

				rc = ap_query_queue(qid, &queue_depth,

						    &device_type);

			}

			ap_dev = to_ap_dev(dev);

			spin_lock_bh(&ap_dev->lock);

			if (rc || ap_dev->unregistered) {

				spin_unlock_bh(&ap_dev->lock);

				put_device(dev);

				device_unregister(dev);

				put_device(dev);

				continue;

			} else

				spin_unlock_bh(&ap_dev->lock);

			}

		if (dev) {

			spin_unlock_bh(&ap_dev->lock);

			put_device(dev);

			continue;

		}
@@ -788,6 +832,8 @@ static void ap_scan_bus(struct work_struct *unused) 
		INIT_LIST_HEAD(&ap_dev->pendingq);

		INIT_LIST_HEAD(&ap_dev->requestq);

		INIT_LIST_HEAD(&ap_dev->list);

		setup_timer(&ap_dev->timeout, ap_request_timeout,

			    (unsigned long) ap_dev);

		if (device_type == 0)

			ap_probe_device_type(ap_dev);

		else
@@ -853,7 +899,7 @@ static int ap_poll_read(struct ap_device *ap_dev, unsigned long *flags) 
	switch (status.response_code) {

	case AP_RESPONSE_NORMAL:

		atomic_dec(&ap_poll_requests);

		ap_dev->queue_count--;

		ap_decrease_queue_count(ap_dev);

		list_for_each_entry(ap_msg, &ap_dev->pendingq, list) {

			if (ap_msg->psmid != ap_dev->reply->psmid)

				continue;
@@ -904,7 +950,7 @@ static int ap_poll_write(struct ap_device *ap_dev, unsigned long *flags) 
	switch (status.response_code) {

	case AP_RESPONSE_NORMAL:

		atomic_inc(&ap_poll_requests);

		ap_dev->queue_count++;

		ap_increase_queue_count(ap_dev);

		list_move_tail(&ap_msg->list, &ap_dev->pendingq);

		ap_dev->requestq_count--;

		ap_dev->pendingq_count++;
@@ -914,6 +960,7 @@ static int ap_poll_write(struct ap_device *ap_dev, unsigned long *flags) 
		*flags |= 2;

		break;

	case AP_RESPONSE_Q_FULL:

	case AP_RESPONSE_RESET_IN_PROGRESS:

		*flags |= 2;

		break;

	case AP_RESPONSE_MESSAGE_TOO_BIG:
@@ -960,10 +1007,11 @@ static int __ap_queue_message(struct ap_device *ap_dev, struct ap_message *ap_ms 
			list_add_tail(&ap_msg->list, &ap_dev->pendingq);

			atomic_inc(&ap_poll_requests);

			ap_dev->pendingq_count++;

			ap_dev->queue_count++;

			ap_increase_queue_count(ap_dev);

			ap_dev->total_request_count++;

			break;

		case AP_RESPONSE_Q_FULL:

		case AP_RESPONSE_RESET_IN_PROGRESS:

			list_add_tail(&ap_msg->list, &ap_dev->requestq);

			ap_dev->requestq_count++;

			ap_dev->total_request_count++;
@@ -1045,6 +1093,25 @@ static void ap_poll_timeout(unsigned long unused) 
	tasklet_schedule(&ap_tasklet);

}



/**

 * Reset a not responding AP device and move all requests from the

 * pending queue to the request queue.

 */

static void ap_reset(struct ap_device *ap_dev)

{

	int rc;



	ap_dev->reset = AP_RESET_IGNORE;

	atomic_sub(ap_dev->queue_count, &ap_poll_requests);

	ap_dev->queue_count = 0;

	list_splice_init(&ap_dev->pendingq, &ap_dev->requestq);

	ap_dev->requestq_count += ap_dev->pendingq_count;

	ap_dev->pendingq_count = 0;

	rc = ap_init_queue(ap_dev->qid);

	if (rc == -ENODEV)

		ap_dev->unregistered = 1;

}



/**

 * Poll all AP devices on the bus in a round robin fashion. Continue

 * polling until bit 2^0 of the control flags is not set. If bit 2^1
@@ -1056,6 +1123,8 @@ static int __ap_poll_all(struct ap_device *ap_dev, unsigned long *flags) 
	if (!ap_dev->unregistered) {

		if (ap_poll_queue(ap_dev, flags))

			ap_dev->unregistered = 1;

		if (ap_dev->reset == AP_RESET_DO)

			ap_reset(ap_dev);

	}

	spin_unlock(&ap_dev->lock);

	return 0;
@@ -1147,6 +1216,17 @@ static void ap_poll_thread_stop(void) 
	mutex_unlock(&ap_poll_thread_mutex);

}



/**

 * Handling of request timeouts

 */

static void ap_request_timeout(unsigned long data)

{

	struct ap_device *ap_dev = (struct ap_device *) data;



	if (ap_dev->reset == AP_RESET_ARMED)

		ap_dev->reset = AP_RESET_DO;

}



static void ap_reset_domain(void)

{

	int i;

drivers/s390/crypto/ap_bus.h

+11 −0
Original line number Diff line number Diff line
@@ -33,6 +33,7 @@ 
#define AP_DEVICES 64		/* Number of AP devices. */

#define AP_DOMAINS 16		/* Number of AP domains. */

#define AP_MAX_RESET 90		/* Maximum number of resets. */

#define AP_RESET_TIMEOUT (HZ/2)	/* Time in ticks for reset timeouts. */

#define AP_CONFIG_TIME 30	/* Time in seconds between AP bus rescans. */

#define AP_POLL_TIME 1		/* Time in ticks between receive polls. */
@@ -83,6 +84,13 @@ struct ap_queue_status { 
#define AP_DEVICE_TYPE_CEX2A	6

#define AP_DEVICE_TYPE_CEX2C	7



/**

 * AP reset flag states

 */

#define AP_RESET_IGNORE	0	/* request timeout will be ignored */

#define AP_RESET_ARMED	1	/* request timeout timer is active */

#define AP_RESET_DO	2	/* AP reset required */



struct ap_device;

struct ap_message;
@@ -95,6 +103,7 @@ struct ap_driver { 
	/* receive is called from tasklet context */

	void (*receive)(struct ap_device *, struct ap_message *,

			struct ap_message *);

	int request_timeout;		/* request timeout in jiffies */

};



#define to_ap_drv(x) container_of((x), struct ap_driver, driver)
@@ -112,6 +121,8 @@ struct ap_device { 
	int queue_depth;		/* AP queue depth.*/

	int device_type;		/* AP device type. */

	int unregistered;		/* marks AP device as unregistered */

	struct timer_list timeout;	/* Timer for request timeouts. */

	int reset;			/* Reset required after req. timeout. */



	int queue_count;		/* # messages currently on AP queue. */

drivers/s390/crypto/zcrypt_cex2a.c

+9 −18
Original line number Diff line number Diff line
@@ -70,6 +70,7 @@ static struct ap_driver zcrypt_cex2a_driver = { 
	.remove = zcrypt_cex2a_remove,

	.receive = zcrypt_cex2a_receive,

	.ids = zcrypt_cex2a_ids,

	.request_timeout = CEX2A_CLEANUP_TIME,

};



/**
@@ -306,18 +307,13 @@ static long zcrypt_cex2a_modexpo(struct zcrypt_device *zdev, 
		goto out_free;

	init_completion(&work);

	ap_queue_message(zdev->ap_dev, &ap_msg);

	rc = wait_for_completion_interruptible_timeout(

				&work, CEX2A_CLEANUP_TIME);

	if (rc > 0)

	rc = wait_for_completion_interruptible(&work);

	if (rc == 0)

		rc = convert_response(zdev, &ap_msg, mex->outputdata,

				      mex->outputdatalength);

	else {

		/* Signal pending or message timed out. */

	else

		/* Signal pending. */

		ap_cancel_message(zdev->ap_dev, &ap_msg);

		if (rc == 0)

			/* Message timed out. */

			rc = -ETIME;

	}

out_free:

	kfree(ap_msg.message);

	return rc;
@@ -348,18 +344,13 @@ static long zcrypt_cex2a_modexpo_crt(struct zcrypt_device *zdev, 
		goto out_free;

	init_completion(&work);

	ap_queue_message(zdev->ap_dev, &ap_msg);

	rc = wait_for_completion_interruptible_timeout(

				&work, CEX2A_CLEANUP_TIME);

	if (rc > 0)

	rc = wait_for_completion_interruptible(&work);

	if (rc == 0)

		rc = convert_response(zdev, &ap_msg, crt->outputdata,

				      crt->outputdatalength);

	else {

		/* Signal pending or message timed out. */

	else

		/* Signal pending. */

		ap_cancel_message(zdev->ap_dev, &ap_msg);

		if (rc == 0)

			/* Message timed out. */

			rc = -ETIME;

	}

out_free:

	kfree(ap_msg.message);

	return rc;

drivers/s390/crypto/zcrypt_pcica.c

+9 −18
Original line number Diff line number Diff line
@@ -70,6 +70,7 @@ static struct ap_driver zcrypt_pcica_driver = { 
	.remove = zcrypt_pcica_remove,

	.receive = zcrypt_pcica_receive,

	.ids = zcrypt_pcica_ids,

	.request_timeout = PCICA_CLEANUP_TIME,

};



/**
@@ -290,18 +291,13 @@ static long zcrypt_pcica_modexpo(struct zcrypt_device *zdev, 
		goto out_free;

	init_completion(&work);

	ap_queue_message(zdev->ap_dev, &ap_msg);

	rc = wait_for_completion_interruptible_timeout(

				&work, PCICA_CLEANUP_TIME);

	if (rc > 0)

	rc = wait_for_completion_interruptible(&work);

	if (rc == 0)

		rc = convert_response(zdev, &ap_msg, mex->outputdata,

				      mex->outputdatalength);

	else {

		/* Signal pending or message timed out. */

	else

		/* Signal pending. */

		ap_cancel_message(zdev->ap_dev, &ap_msg);

		if (rc == 0)

			/* Message timed out. */

			rc = -ETIME;

	}

out_free:

	kfree(ap_msg.message);

	return rc;
@@ -332,18 +328,13 @@ static long zcrypt_pcica_modexpo_crt(struct zcrypt_device *zdev, 
		goto out_free;

	init_completion(&work);

	ap_queue_message(zdev->ap_dev, &ap_msg);

	rc = wait_for_completion_interruptible_timeout(

				&work, PCICA_CLEANUP_TIME);

	if (rc > 0)

	rc = wait_for_completion_interruptible(&work);

	if (rc == 0)

		rc = convert_response(zdev, &ap_msg, crt->outputdata,

				      crt->outputdatalength);

	else {

		/* Signal pending or message timed out. */

	else

		/* Signal pending. */

		ap_cancel_message(zdev->ap_dev, &ap_msg);

		if (rc == 0)

			/* Message timed out. */

			rc = -ETIME;

	}

out_free:

	kfree(ap_msg.message);

	return rc;

drivers/s390/crypto/zcrypt_pcicc.c

+9 −18
Original line number Diff line number Diff line
@@ -82,6 +82,7 @@ static struct ap_driver zcrypt_pcicc_driver = { 
	.remove = zcrypt_pcicc_remove,

	.receive = zcrypt_pcicc_receive,

	.ids = zcrypt_pcicc_ids,

	.request_timeout = PCICC_CLEANUP_TIME,

};



/**
@@ -501,18 +502,13 @@ static long zcrypt_pcicc_modexpo(struct zcrypt_device *zdev, 
		goto out_free;

	init_completion(&work);

	ap_queue_message(zdev->ap_dev, &ap_msg);

	rc = wait_for_completion_interruptible_timeout(

				&work, PCICC_CLEANUP_TIME);

	if (rc > 0)

	rc = wait_for_completion_interruptible(&work);

	if (rc == 0)

		rc = convert_response(zdev, &ap_msg, mex->outputdata,

				      mex->outputdatalength);

	else {

		/* Signal pending or message timed out. */

	else

		/* Signal pending. */

		ap_cancel_message(zdev->ap_dev, &ap_msg);

		if (rc == 0)

			/* Message timed out. */

			rc = -ETIME;

	}

out_free:

	free_page((unsigned long) ap_msg.message);

	return rc;
@@ -544,18 +540,13 @@ static long zcrypt_pcicc_modexpo_crt(struct zcrypt_device *zdev, 
		goto out_free;

	init_completion(&work);

	ap_queue_message(zdev->ap_dev, &ap_msg);

	rc = wait_for_completion_interruptible_timeout(

				&work, PCICC_CLEANUP_TIME);

	if (rc > 0)

	rc = wait_for_completion_interruptible(&work);

	if (rc == 0)

		rc = convert_response(zdev, &ap_msg, crt->outputdata,

				      crt->outputdatalength);

	else {

		/* Signal pending or message timed out. */

	else

		/* Signal pending. */

		ap_cancel_message(zdev->ap_dev, &ap_msg);

		if (rc == 0)

			/* Message timed out. */

			rc = -ETIME;

	}

out_free:

	free_page((unsigned long) ap_msg.message);

	return rc;